Just one day after it was revealed that Catherine Zeta-Jones had recently checked into a mental health facility for treatment of her bipolar II disorder, she stepped out with husband Michael Douglas for some pizza served with a side of optimism.

"They seemed great," a spy tells People of the couple's outing on Thursday to Pizza Post in Greenwich, Conn. "They looked very happy together."

According to the snitch, the other diners were "thrilled" to be eating so close to the famous duo, who were "gracious and low-key" as they waited to get their food packed up to go (they have a house nearby).

And for those of you who like to keep track of the stars' culinary habits (hey, no judgment), Access Hollywood says they ordered a Margherita pizza, a salad, and two sandwiches (perhaps for kids Carys, 7, and Dylan, 10).

"They were in good spirits," adds a staffer.

Zeta-Jones, 41, reportedly spent about five days in a treatment center for problems brought on by "the stress of the past year," which has included Douglas' battle with throat cancer and the 5-year prison sentence meted out to his son, Cameron, on drug charges.

"There's no question it's been a stressful year," a confidant explains to People. "Catherine has had deal with Michael's illness, and that's been hard. She went in for a few days because she's about to start working, and wanted to make sure she's in top form, which she is."

Another stressor for the pair: The actor's ex-wife, Diandra Douglas, who returned to a New York court this week to make another attempt to secure half his earnings from "Wall Street: Money Never Sleeps."

Michael, 66, didn't attend the hearing, although his lawyer pointed out that Diandra, who has pocketed more than $50 million from their 2000 divorce, "should be ashamed of herself."